Cold weather shipping reminder

Jim Fairles  

Animal Health Laboratory, University of Guelph, Guelph, ON

AHL Newsletter 2019;23(4):2-3.

Winter has come a little early this year! Given that, we need to start thinking about preventing samples from freezing. Specimens such as EDTA blood are rendered useless when frozen. Formalin will also freeze, which creates artifacts in fixed tissue. The photo on the left is a normal H&E section of lymph node and the photo on the right is the same tissue that was frozen before processing and preparation of histopathology slides (Fig. 1).

Figure 1.  Histopathologic sections of a lymph node (H&E). The tissue on the left was processed normally. The node on the right was frozen prior to processing. Note the severe distortion produced by vacuolation of tissue.

It can be difficult to protect samples that are shipped during the winter from severe cold. To inhibit or reduce formalin freezing, add 1 mL of ethanol per 10 mL of formalin. Samples that should not be frozen should be shipped inside insulated containers with minimal cold packs. Use of room temperature cold packs will help prevent temperatures from dipping too low. If you have any concerns about the best way to ship critical samples, please contact the AHL.  ahlinfo@uoguelph.